1. Field of the Invention
The present invention relates generally to semiconductor packaging. More particularly, the present invention relates to a semiconductor flip chip package utilizing wire bonding for net switching.
2. Description of the Prior Art
Flip chip technology is widely used in a variety of consumer products where form factor is key, for example, mobile phones, camcorders or personal digital assistants (PDAs). The adoption of flip chip package in many applications is driven by performance needs and the ability to achieve smaller die with a flip chip design. The smaller die translates into a greater number of die per wafer. While the flip chip assembly benefits high performing devices, its cost is the major challenge for main stream applications. Thus, major efforts continue to be made to reduce costs.
FIG. 1 is a perspective top view of a flip chip package with a specific bump option according to the prior art. FIG. 2 is a schematic, cross-sectional diagram taken along line I-I′ of FIG. 1. As shown in FIG. 1 and FIG. 2, the prior art flip chip package 1 comprises a carrier substrate 2 and a flip chip 3 mounted on a top surface of the carrier substrate 2. The flip chip 3 is electrically coupled to the carrier substrate 2 through a plurality of bumps 4 which are applied to an active surface of the flip chip 3 according to the specific bump option. In a multiple I/O-to-1 ball case, for example, two bump sites 5a and 5b disposed on the active surface of the flip chip 3 are aligned correspondingly with two pads 6a and 6b provided on the top surface of the carrier substrate 2.
The two pads 6a and 6b are electrically coupled to the same solder ball 7 on a bottom side of the carrier substrate 2 by way of the common circuit trace 6c. According to the specific bump option, the bump site 5b is empty, that is, no bump is formed on the non-selected bump site 5b, while a bump 4a is applied to the selected bump site 5a, whereby a specific function of the flip chip package can be determined according to the specific bump option.
The above-described prior art flip chip package is costly partly because each of the bump options requires a different bumping mask. In addition, IC design houses usually encounter annoying die version management problem when keeping the die for flip chip assembly in stock. This is because different bump options result in different die versions. Due to the nature of the flip chip package, once the bump option is used and the die version is determined, there is no way to change or rework.